1. No category

Tailor-made polymeric materials
for collectors and heat storages
Prof. Dr. Gernot M. Wallner
Subtask Leader C
Johannes Kepler University Linz, Austria
Institute of Polymeric Materials and Testing
gernot.wallner@jku.at
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Presentation Outline
Introduction and Background


Development of Polymeric Materials
Main Fields of Application and Success Factors
Subtask C: Structure, Partners and Selected Results


Main Topics and involved Partners
3 selected Case Studies on Plastics for:
 Overheating controlled flat-plate collectors
 Drainback flat-plate collectors
 Heat storage liner materials
Summary and Outlook

Solarthermal Market Development

Material Demand
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
The importance of the polymer industry
Development of plastics and steel worldwide (in terms of volume)
Solarthermal collector additions in 2012:
55,4 GWth ~ 79 mio. m2 ~ 1.6 mio. t material !!!
Source: Plastics Europe, D (2008)
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Plastics - most widely used material class
 Civil & infrastructure
engineering (B&C)
 Medical
technologies
 Telecommunication
 Automotive
engineering
Lens holder of
DVD player
3 mm
 Precision
engineering &
mechatronics
 Packaging
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Plastics - main features and success factors
 Freedom of
design
 Wide range:
property/performance
(tailor-made materials)
LED optics
 Multifunctional
integration
 Combination of
process technologies
 Composites &
hybrid materials
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Plastics - Market penetration
4 main prerequisites for
market acceptance:
 improved performance
(functionality)
 enhanced cost
effectiveness
 guaranteed quality and
durability
 attractive/multifunctional design
What needs to be done to accelerate
innovation & market penetration?
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Projects of Subtask C on Materials
Project Title
Focus
C1
Multi-Functional
Polymeric Materials
• Materials for „All-polymeric“
Collectors
• Materials for System
Components incl. Heat Storages
C2
Processing and Evaluation
of Components
• Extrusion and Injection
Moulding of Components
• Joining techniques
C3
Methods for Testing and
Characterization
• Quality assurance
• Aging and durability
characterization
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Partners of Subtask C on Materials
10 Countries 13 Company partners
10 Scientific partners
Austria,
Belgium,
Brasil,
Germany,
Netherlands,
Norway,
Portugal,
Slovenia,
Switzerland,
USA
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Overheating controlled collectors
Thermotropic materials – Requirements and Achievements
(Univ. of Leoben (Austria); Univ. of Minnesota (USA); EMS (Switzerland))
Switching performance of
Key-property requirementscommercial
for
impact modified
thermotropic materials: grades is not appropriate.
Absorbance: negligible
Thermotropic
layer> 90%
Transmittance
(clear):
should be(switched):
applied to> 50%
Reflectance
the absorber.
Switching
temperature: 80-90°C
specific
heat




Development grades:
• min. thickness: 3 mm
• optimization required
1 W/g
Source: Hartwig, 2003
solar
transmittance [%]
80
hemisph.
diffuse
70
60
50
40
20
30
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
40
50
60
temperature [°C]
70
80
Overheating controlled collectors
Absorber materials for overheating protected collectors
(Borealis, Univ. of Linz, AEE INTEC, Univ. of Innsbruck (Austria))
Overheating control by backcooling
System type & service requirements
Diverting
valve (Valcoo,
CN)
 Pressurized
system
with overheating protection
 service life: 20 years
 region: Graz (Austria)
Key-property requirements for absorber materials




Max. absorber temperature
in stagnation: ~ 92oC
solar absorption: 93-95%
thermal stability: >100°C
low temperature capability: -30°C
long-term stability in water/glycol:
 75-100°C: > 3,500 h (DHW)
> 7,000 h (SH)
 0-75°C:
> 150,000 h
 pressure: max. 1,5 bar
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Overheating controlled collectors
Development and lifetime estimation for PP absorber materials
(JKU IPMT; AEE INTEC, Austria)
104
10
Overheating protected
collector system for DHW
(domestic hot water)
Graz
Athens
Pretoria
Fortaleza
Lifetime
Beijingmodelling:
•
•
3
PP-B2
102
10000
ongoing
1000
Extrapolation by Gugumus
approach
Cumulative damage model (Miner’s
rule)  failure time (tf) 100
𝑖=𝑛
1
101
time-to-embrittlement, d
frequencies, h/a
105
100000
𝑡𝑖
𝑡𝑓 =
experimental data PP-B2
Gugumus (1999) data 0.1% AO-1
Gugumus (1999) data 0.05% AO-1
predicted data PP-B2
𝑓𝑖 𝑇𝑖 , 𝜎𝑖
𝑡𝑡𝑜𝑡 /𝑡10
𝑖=1
100
-20
0
20
40
60
80
100
1
2,4
absorber temperature, °C
Lifetime, years
Graz, AT
2,6
2,8
3
3,0
3,2
-1
10 (1/T), K
Athens, GR
Pretoria, RSA
Fortaleza, BR
Beijing, CHN
PP-B1
21
15
14
8
23
PP-B2
32
25
24
15
34
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Overheating controlled collectors
Development and lifetime estimation for PP absorber materials
(Univ. Linz, Borealis, AEE INTEC (Austria))
104
10
Graz
Novel material PP-B2
is now used commercially!
Overheating protected
collector system for DHW
(domestic hot water)
Athens
Pretoria
Fortaleza
Beijing
3
102
101
100
-20
PP-B2
0
20
40
60
80
100
time-to-embrittlement, d
frequencies, h/a
105
100000
10000
ongoing
1000
100
1
2,4
absorber temperature, °C
Lifetime, years
PP-B1
PP-B2
MAGEN eco-ENERGY
(Israel, Kibbuz
Magen)
Graz, AT
Athens,
GR
Pretoria, RSA
www.magen-ecoenergy.com
21
15
14
32
25
experimental data PP-B2
Gugumus (1999) data 0.1% AO-1
Gugumus (1999) data 0.05% AO-1
predicted data PP-B2
10
2,6
2,8
3
3,0
3,2
-1
10 (1/T), K
Fortaleza, BR
24
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Beijing, CHN
8
23
15
34
Drainback flat-plate collectors
Requirements for absorber materials in drainback collectors
(Univ. Oslo, Aventa (Norway))
System type & service requirements
 low-pressure drainback system
 service life: 20 years
 region: Oslo (Norway)
Key-property requirements for
absorber materials
 solar absorption: 93-95%
 thermal stability: >150°C
 long-term stability in water:
 < 80°C: > 160,000 h
 short-term stability
in air/water vapor:
High performance
plastics required; focus on:
 80-150°C:
> 8,000 h (DHW)
• Polyphenylenesulfide
(PPS)
 no pressure• Polyphenyleneether (PPO)
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Drainback flat-plate collectors
Processing, testing and lifetime estimation of PPS
(Univ. Oslo, Aventa (Norway), Chevron Philips (Belgium), DS Smith (France), ISE (Germany))
Extrusion
(XE4500BL)
Absorber
sheet
Cutting
to standard
lengths
Hot-plate welding
IR - welding
France
PPS
Granulates
Welding
Blow molding
of Endcaps
(XE5032 BL, 30%GF)
Estimated lifetime: ~ 20 years
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Drainback flat-plate collectors
Multifunctional coatings for PPS absorbers
Estethic colors
(NIC, Color (Slovenia), Univ. Oslo, Aventa (Norway))
Thickness Insensitive Spectrally Selective
(TISS) paints
Self-cleaning capability
• Al flakes
• Spinel pigments
• Organic binder
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Heat storage liner materials
Liner materials for seasonal hot water storages
(AGRU, Univ. of Linz (Austria))
Criteria for liner materials:
Example
 Flexibility for easy installation:
 E ≈ 600 MPa (at RT)
Floating insulating cover
Polymeric liner
 Liner thickness: ≈ 2 mm
 Key requirements:
 Tmax = 95°C
 4,000 h/a ≈ 65-85°C
 4,000 h/a ≈ 30-60°C
 Environment:
 Water heat carrier
 Air / water vapor
Dimensions:
 Soil chemistry (minerals)
 Volume: 1.000 – 100.000 m3
 Service lifetime: ≥ 30 years
 Demand of liner: 250 – 25.000 m2
SUNSTORE4, Marstal, DK (75 000 m³ water)
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Heat storage liner materials
Accelerated aging characterization by Specimen Miniaturization
(Univ. of Linz (Austria))
Automized production
of micro-sized specimen
Aging equipment (air,
water water vapor)
Aging characterization
and indicators
Mechanics (Tensile Testing):

Strain at break (εB)
Spect
roscopy:

Carbonyl index (C.I.)
Thermoanalytical Methods:

Oxidation onset temperatur
(OOT)
Chromatography:

Content of stabilizers (esp.
antioxidants)
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Heat storage liner materials
Durability of polyolefin compounds (benchmark vs. novel grades)
(Univ. of Linz, AGRU, APC (Austria))
Water aging more severe than air
aging.
Novel polypropylene (PP) exhibit a
better durability.
Lifetime estimation
 No embrittlement for all grades due to
o
exposure in hot air and water at 95 C up to
900d (2.5 years).
B[%]
 Ranking: PE-RT 2 > PE-RT 1 > PE-HD
PE-HD
900
PE-RT 1
115°C, water
600
300
0
900
B[%]
Polyethylene (PE) grades:
PP-R 0
115°C, air
600
300
0
0
100 200 300 400 500 600 700 800 900
 Continuation of experiments
Spin-off:
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Time [d]
Summary and Outlook
Global Solar Thermal Heat based on 100% Renewable Energy Scenarios
(1)
To keep up with the ambitious 100% scenarios, and
14,000
(2) to strengthen (or even maintain) its position as a main component in a future solar
12,000
technology mix,
the solar-thermal industry needs a strong innovation push by enhanced R&D efforts.
TWh/a
10,000
8,000
3,000
6,000
2,500
2,000
TWh/a
4,000
2,000
0
2000
1,500
1,000
500
2010
2020
2030
2040
02050
2000
2005
2010
2015
2020
Source: K. Holzhaider (2014)
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Summary and Outlook
TWh/a
Global Solar Thermal Heat based on 100% Renewable Energy Scenarios
(1) To keep up with the ambitious 100% scenarios, and
(2)
to strengthen (or even maintain) its position as a main component in a future solar
14,000
technology mix,
Energy [R]Evolution E[R]Scenario
12,000
the
solar-thermal industry needs a strong innovation push by enhanced
R&D efforts.
(3)
Apart from significant polymer-induced innovations, there isEnergy
no other
single- Reference
[R]Evolution
10,000
Scenario
innovation driver in sight to achieve the more ambitious scenarios.
8,000
6,000
2,500
Real development of global
solar thermal heat production*
2,000
TWh/a
4,000
2,000
0
2000
The Energy Report ECOFYS Scenario
3,000
1,500
1,000
500
2010
2020
2030
2040
02050
2000
2005
2010
2015
2020
Source: K. Holzhaider (2014)
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014
Summary and Outlook
Global Cumulative Material Demand for Polymer Based Solar Thermal Systems
million t
600
Polymers
500
Mineral Wool
400
Glass
300
Stainless Steel
200
Copper
100
0
2010
Aluminium
2020
2030
2040
2050
K. Holzhaider (2014)
(1) Low temperature heat supply is Year
currently based on fossil (carbon)Source:
fuels.
(2) To achieve 100% renewable energy scenarios an average annual plastics demand of
8.2 million t/a would be needed.
 Highly attractive market perspective for the oil/gas and plastics industry.
Polymeric Materials for Solar Thermal Applications – Final Presentation 10/2014